Water pump motors of the dry winding set type typically include a rotor mounted in a rotor chamber and a stator assembly, having laminations and a winding set, operatively associated with the rotor assembly. The rotor assembly shares a bearing-supported shaft with an impeller of the pump. Water pump motors generally have some type of cooling to extend the operating capability thereof. In general, it is desirable to maintain the temperature of such devices below a predetermined limit in order to prevent deterioration of the device through thermal breakdown or distortion due to thermal expansion of elements of the device. In certain pump motors, the stator assembly is isolated from the rotor chamber such that fluid from the pump may enter the rotor chamber, submerge the rotor, and cool the bearings and stator assembly by heat exchange with the fluid, without the fluid contacting the winding set of the stator assembly.
Water pump motors for use in todays automobiles are electronically controlled and generally have an electronic control unit electrically coupled to the winding set of the motor. The electronic control unit generates heat that may limit the operating temperature of the pump motor. Thus, there is a need to provide cooling not only of the bearings and stator assembly of the device, but also of the electronic control unit thereof.